assiguors to Contourpedic Corporation Filed June 8, 1972, Ser. No. 261,049 Int. Cl. B29d 27/00 US. Cl. 264-45 20 Claims ABSTRACT OF THE DISCLOSURE An impression forming assembly is provided and a flexible base container filled with particulate material positioned on a horizontal platform and a flexible back container in fluid communication with a reservoir of particulate material positioned on a vertical wall spacially juxtaposed to the horizontal platform. A human is positioned on the containers and the pressure in the back container is reduced until the particulate material becomes interlocked and the container assumes a rigid configuration. The back container is thereafter pressurized and particulate material is introduced into the container. The pressure in the second container is reduced until the particulate material becomes interlocked and the back container assumes a rigid configuration. The rigid containers constitute an impression set from which a contoured cushion is subsequently prepared.

BACKGROUND OF THE INVENTION This invention relates to an apparatus and process for the formation of contoured impressions, and more particularly to an apparatus and process for the formation of a personalized contoured impression of the gluteus maximus, posterior portion of the thighs, and at least a portion of the back (particularly the lumbar area) of a human including the subsequent formation of a personalized contoured seat cushion having vertical and horizontal sections.

Temporary confinement of a human within a wheelchair or like erect-positioning apparatus for extended periods of time is discomforting and fatiguing due to the inability of such apparatus to provide proper support to the body. Confinement to such apparatus by humans afflicted with a permanent disability or handicap produced by accident or incurable maladies compound the problems of discomfort and fatigue.

While contoured seats and/or cushions for general use have been designed and manufactured for automobile seats, stadium chairs, oflice chairs, and the like, the requirements of permanently handicapped or disabled humans, however, have for the most part been ignored with solutions heretofore advanced meeting with limited success; e.g. a flexible cushion provided with a semi-rigid gel. Personalized contoured cushions or inserts for use with wheelchairs have been formed using time consuming procedures for forming a negative impression employing plaster of Paris bandages, heat-formed thermoplastic materials and the like. Such procedures, however, are convenient to the patient as well as to the technician, and have been found only partially satisfactory. Additionally, it has been generally found necessary to sculpture the thus-formed cushion or insert after formation but prior to upholstering to achieve satisfactory results with a con comitant increase in production costs. The formation of an impression of another part of the body; e.g. a foot, is described in U.'S. Pat. No. 2,472,754 to Meade.

OBJECTS OF THE INVENTION It is an object of the present invention to provide an improved apparatus and process for forming a contoured impression of the gluteus maximus and at least a portion of the back which overcome the disadvantage of the prior art.

Another object of the present invention is to provide an improved apparatus and process for readily forming a contoured impression for the subsequent manufacture of a contoured cushion or insert, particularly for erect-positioning apparatus.

Still another object of the present invention is to provide an improved apparatus and process for forming a contoured impression whereby the impression may be conveniently taken with the human in a wheelchair or like erect-positioning apparatus.

A further object of the present invention is to provide an improved apparatus and process for forming a contoured impression whereby sculpturing of the resulting contoured cushion or insert is essentially eliminated prior to the upholstering thereof.

A still further object of the present invention is to provide an improved apparatus and process for forming a contoured impression whereby the weight of the patient is evenly distributed prior to the formation of the impression.

Still another object of the present invention is to provide an improved process and apparatus for forming a contoured cushion of the gluteus maximus and the back including the lumbar area of a human.

SUMMARY OF THE INVENTION These and other objects of this invention are achieved by providing an impression forming assembly including a flexible container including particulate material positioned on a horizontal platform and a flexible container in fluid communication with a reservoir of particulate material positioned on a vertical wall spacially juxtaposed to the horizontal platform. A-fter comfortably positioning the human on the containers, the pressure in the first container is reduced to a point where the particulate material becomes interlocked and the container assumes 'a rigid configuration. Thereafter, the second container is slightly pressurized and particulate material caused to flow into the container. The pressure in the second container is then reduced to the point where the particulate material becomes interlocked and the container assumes a rigid configuration. As used herein, particulate material includes rigid solid or hollow spheres or granules as well as hollow, semi-rigid balls, such as polypropylene balls.

A contoured cushion forming assembly is also provided including an impression shell comprised of a horizontal platform or base and a vertical wall, with the platform and base being provided with spacer elements. A flexible base container or envelope including particulate material is positioned on the horizontal platform. A flexible back container or envelope is disposed on the vertical wall relative to the base container and extends over the top portion of the vertical wall. The portion of the container extending over the top portion of the wall forms a reservoir for the particulate material. Each flexible container is provided with a connector device in fluid communication through a conduit with a pump. The human whose impression is to be formed is comfortably positioned on the flexible containers with the base container being subsequently pressurized to a pressure such that the gluteus maximus of the human is in nominal contact with the top surface of the particulate material therein. The pressure within the seat container is thereafter reduced thereby causing the gluteus maximus of the human to slowly contact the particulate mass in a manner to cause the particulate material to flow and the surface thereof to conform eventually to the surface of the gluteus maximus of the human as well as a portion of the posterior portion of the thighs, if desired. The pressure within the base container is further reduced (i.e. a portion of the gaseous media within the container is withdrawn) until the particles forming the particulate material becomes rigid or immovable relative to one another by frictional and interlocking forces thereby forming a contoured impression of the gluteus maximus of the human.

Thereafter, the back container is pressurized and the particulate material caused to flow from the reservoir into that portion of the pressurized container between the human and the vertical wall of the impression shell. The pressure within the back container is then reduced until the particulate material similarly becomes rigid thereby forming a contoured impression of a portion of the back preferably including the lumbar area of the human in proper relationship to the contoured impression of the gluteus maximus thereof.

The containers or impression set are overlayed with a releasing agent or material and an impression cover is positioned thereover to form a cavity therein with the impression shell. A rigid foam-forming composition is introduced into the enclosure between the impression set and the impression cover and upon curing thereof the impression cover is removed together with a positive impression form of the impression set. The impression cover including the positive impression form is thereafter positioned and clamped on an impression shell and a flexible foam-forming composition is caused to flow into the cavity between the impression shell and the positive form. After an appropriate time for curing, the impression shell and cover are separated and a personalized contoured cushion member is removed for subsequent upholstering. Thus, a contoured cushion is readily prepared which does not require the human to assume awkward positions for extended periods of time and which is easily understood and may be applied by persons untrained in orthopedics.

BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the present invention as well as other objects and advantages thereof will become apparent upon consideration of the detailed disclosure thereof, especially when taken with the accompanying drawings, wherein like numerals designate like parts throughout, and wherein:

FIG. 1 is an exploded view of the contoured cushion forming assembly of the invention;

FIGS. 2 to 5 are cross-sectional schematic views illustrating the method of forming the impression set;

FIG. 6 is an isometric view schematically illustrating the preparation of the positive impression form; and

FIG. 7 is an isometric schematic View illustrating the formation of the contoured cushion.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1 there is illustrated a preferred embodiment of the impression forming assembly of the invention comprised of an impression shell, generally indicated as 10; seat and back spacers, generally indicated as 12 and 14, respectively; seat and back containers, generally indicated as 16 and 18, respectively; and a pump-motor assembly 20. The contoured cushion forming assembly is comprised of the impression forming assembly together with a release medium, generally indicated as 22, and an impression cover, generally indicated as 24. The impression shell 10 is generally of an L-shaped configuration and is formed with a horizontal section 26 and a vertical wall section 28 joined generally at a curved section of the shell 10. The horizontal section 26 and the vertical wall section 28 are formed with up turned side walls 26:: and 26b, and 28a and 28b, respectively. The sections 26 and 28 of the impression shell 10 may be provided with a plurality of orifices 30, as more fully hereinafter described.

The seat spacer 12 is formed of a resilient material with a main body portion 32 and an outer lip portion 34 and is fixedly positioned on the horizontal section 26 of the shell 10, such as by screws (not shown) threaded through orifices 30 therein. The back spaced 14 is formed of a resilient material with a main body portion 36 and an outer lip portion 38 and is fixedly positioned on the vertical wall section 28 of the shell 10, such as by screws (not shown) threaded through orifices 30 therein.- In this re spect, other means for securing the spacers 12 and 14 may be used, e.g. clips. The spacer 14 is provided with pegs 40 for centering the back container 18. Both the spacers are formed of rigid or semi-rigid material and are generally of one piece construction utilizing conventional techniques, such as molding. The spacers 12 and 14 function to minimize or prevent bottoming out of the human onto the surface of the impression shell thereby inhibiting the formation of an effective impression. It is understood that the spacers may be omitted if the impression forming apparatus is to be used for light duty; i.e. the impressions of young children.

The seat container or envelope 16 is formed from flexible films of materials, such as polyurethane films, vinyl films, polyvinyl films and rubber coated nylon, sealed at the edge thereof by conventional techniques; e.g. heat sealing, and is provided with a conduit 42 connected to a tube 44. The back container or envelope 18 is similarly formed from a flexible film and is provided. with a conduit 46 connected to a tube 48. Each of the containers are provided with a particulate material or granules, generally indicated as 50, which frictionally interlock when subjected to reduced pressure within a flexible container.

The seat container 16 is provided with a quantity of particulate material 50 which generally fills the container under atmospheric pressure whereas the quantity of par ticulate material 50 provided in the back container 18 is substantially less than the volume thereof at atmospheric pressure. The optimum quantity of particulate material for each container may be readily determined with regard to the design size of the containers. The back container 18 is provided with orifices 52 which cooperate with the pegs 40 mounted on the back spacer 14 to properly fix the relative position of the back container 18 with respect to the seat container 16. The length of the back container 18 is greater than the height of the vertical panel 28 of the shell 10 to form a reservoir for the particulate material, generally indicated as 54, by the excess portion thereof extending over the topof the vertical panel 28. Accordingly, when disposed on the back spacer 14, all of the particulate material 50 is preferably positioned within the reservoir 54 before the process of impression forming.

The pump-motor combination 20 including a tube 58 may be of any commercially available design having the ability to increase the pressure in the containers to above atmospheric pressure and to reduce the pressure therein to at least about 25 in. of Hg. Additionally, the pumpmotor combination should be light weight for ease of handling.

FIGS. 2 to 5 schematically illustrate the method of impression forming wherein FIG. 2 shows the impression forming assembly in an initial configuration; i.e. the seat container 16 at atmospheric pressure disposed on the seat spacer 12 positioned on the spacer 12 disposed on the horizontal section 26 of impression shell 10 with essentially even distribution of the particulate material, and the back container 18 positioned on the spacer 14 mounted on the vertical wall section 28 of the shell 10, such that the particulate material 50 is disposed within the reservoir 56. The human whose impression is to be taken is comfortably positioned on the assembly (FIG. 3). The pressure within the seat container 16 is increased by pump 20 placed in fluid communication with the container 16 by tubes 58 and 44 via conduit 42 to raise the gluteus maximus of the patient above the surface of the particulate material within the container 16. The container 16 is then vented, preferably slowly, to atmospheric pressure to permit the particulate material to flow and thereby cause the surface thereof to conform to the surface of the gluteus maximus including a posterior portion of the thigh. The pressure is further reduced to below atmospheric, generally at least about 25 in. of Hg whereat the frictional forces between the particulate material interlock causing the container 16 to assume a rigid configuration. Air is prevented from re-entering the container 16 by a single end shut-off valve assembly 58 disposed on the end of the tube 44. It is understood that other means may be employed, such as clamps and the like.

FIG. 3 illustrates the initial step in forming the impression of a portion of the back including the lumbar area of the human wherein the container 18 is nominally pressurized to move the torso of the human away from the spacer 14 disposed on the vertical wall section 28 of the container 18 and to provide a passageway for the particulate material 50 from the reservoir 56 of the container 18. The reservoir 56 including particulate material is raised above the top portion of the vertical wall section 28 of the shell to permit the particulate material to flow into that portion of the container 18 between the human and the wall section 28. Thereafter, the reservoir 56 is lowered and the container 18 vented to atmospheric pressure with the subsequent evacuation thereof to a pressure of at least about 25 in. of Hg to form a rigid back container 18. It will be appreciated that the particulate material in both containers may be manually manipulated to insure effective contouring of an impression prior to or during depressurizing of the container.

Should the formed impression of the back be unsatisfactory, the impression may be retaken by lifting that portion of the container 18 having the orifices 52 over the pegs 40 and removing the container 18 from the impression shell 10. The container 18 is then vented to atmospheric pressure and the particulate material 50 returned to the reservoir 56. The container 18 is thereafter re-positioned on the shell 10 with proper relationship to the seat container 16 being insured by placing the orifices 52 provided in the back container 14 over the pegs 40 of the back spacer 14 being disposed within. The process of forming the back impression is then repeated as hereinabove disclosed. It is understood that other means, such as guide slots and the like may be used to center the back container 18 on the impression shell 10. Additionally, centering means may be provided on the vertical wall section instead of on the spacer 14, e.g. where a spacer element is not required.

Upon removal of the human, the impression forming assembly is now ready for the process of making a contoured cushion. A releasing agent is preferably sprayed on or overlayed on the impression set (the combination of both containers) to facilitate removal of the positive impression form as more fully hereinafter discussed. It has been found that a thin sheet of rubber is effective for this purpose as well as silicon sprays. The impression cover 24 including an orifice 60 is positioned over the impression shell 10 including the impression set, as illustrated in FIG. 6, and clamped in place thereto by suitable means (not shown). The impression cover 24 is generally L-shaped and is formed with a horizontal section 62 and a vertical Wall section 64 joined generally at a curved section of the impression cover 24. Extending downwardly and forwardly from the end of the horizontal section 62 is a leg section 66. The horizontal section 62 and the vertical wall section 64 are formed with downturned side walls 62a and 62b, and 64a and 64b, respectively, which cooperate in essentially fiuid tight relationship with the side walls 26a and 26b, and 28a and 28b,

of the horizontal section 26 and the vertical wall section 28, respectively, of the impression shell 10. While a fiuid tight relationship is desirable, the side walls may be spaced apart provided an excessive flow of foam-forming composition therethrough does not result, as more fully hereinafter discussed. The terminal portion of the impression shell 10 and the impression cover 24 are spaced apart to provide a means for the release of gases evolved during the curing of a foam-forming composition.

A rigid foam-forming composition, such as a rigid urethane plastic #PT-2319-12 W/S available from Chemical Components, Inc., is introduced into the enclosure or cavity formed by the impression shell 10 including the impression set and impression cover 24. Upon curing, the expanded foam forms a positive impression 70 of the impression set. The impression shell 10 and the impression cover 24 are readily separated as a result of the use of the releasing material with the positive impression 70 generally adhering to the impression cover 24 depending on the material of construction for the cover 24 and the type of foam-forming composition.

The impression cover 24 together with the positive impression 70 is positioned on a blank impression shell 10 as illustrated in FIG. 7 and clamped in place after overlaying the surfaces with a releasing agent. In this regard, the impression shell 10 of the impression forming assembly may be used after removing the containers 16 and 18 and the spacer elements 12 and 14. A flexible foam-forming composition such as a flexible urethane plastic (Rubicol XP-509, a registered trademark of Rubicon Chemicals, Inc.), is introduced into the enclosure or cavity formed by the impression shell 10 and the impression lid 24 including the positive impression 70. Upon curing the expanded foam forms a negative impression cushion 72, the surface of which conforms to the surface of the impression set. Upon removal of the cushion 72, excess material is trimmed about that portion of the cushion 72 corresponding to the gaseous release spaces or means provided by the assembled configuration of the impression shell 10 and cover 24. While such gaseous release means are illustrated as spaces between the terminal portions of the impression shell 10 and cover 24, it is understood that orifice means may be judiciously disposed therein whereby the aforementioned spaces may be eliminated.

While the method of forming the impression cushion 72 has been discussed with reference to a flexible foamforming composition, it is understood that the composition may be varied to achieve diverse degrees of flexibility depending on the requirements of the human whose impression is being taken. Additionally, while the process and apparatus of the invention has been described with reference to forming the impression of a portion of the back including the lumbar area of a human, it is understood that an impression of the entire back; i.e. from the head to the gluteus maximus, of a human may be taken; e.g. for paralyzed or spastic children. Further, while discussed with reference to the formation of impression cushions for disabled or handicapped humans, the apparatus and process of the invention may be used to prepare contoured cushions for any human for any desired purpose. Further, the impression device of the invention need only include two platforms having a relative angle therebetween normally found in erect-positioning apparatus as well as semi-reclining apparatus, with the contoured cushion forming assembly including top and bottom mold forms of a desired configuration.

While the invention has been described in connection with an examplary embodiment thereof, it will be understood that many modifications will be readily apparent to those of ordinary skill in the art; and this application is intended to cover any adaptations or variations thereof. Therefore, it is manifestly intended that this invention be only limited by the claims and the equivalents thereof.

What is claimed is:

1. An impression forming assembly which comprises:

a shell having a horizontal section and a vertical wall section;

a first flexible container including particulate material therein and provided with conduit means, said first container being positioned on said horizontal section of said shell; and

a second flexible container provided with first and second conduit means, said second container being disposed on one side of said vertical wall, one of said conduit means being in fluid communication with a reservoir of particulate material.

2. The impression forming assembly as defined in Claim 1 wherein a portion of said second container extends over said vertical wall section and forms said reservoir.

3. The impression forming assembly as defined in Claim 1 wherein said vertical wall section and said first portion of said second container are provided with means for fixing the position therebetween.

4. The impression forming assembly as defined in Claim 1 wherein resilient spacer means are disposed between said horizontal section of said shell and said first container.

5. The impression forming assembly as defined in Claim 1 wherein resilient spacer means are disposed between said vertical wall section and said first portion of said second container. U

6. The impression forming assembly as defined in Claim 1 additionally comprising a pump means including conduit means in fluid communication with said conduit means of said containers for pressurization and evacuation thereof.

7. A contoured cushion forming assembly which comprises a bottom shell having a horizontal section and a vertical wall section;

a first flexible container including particulate material therein and provided with conduit means, said first container being positioned on said horizontal section of said shell;

a second flexible container provided with a first and second conduit means, said second container being disposed on one side of said vertical 'wall, one of said conduit means being in fluid communication with a reservoir of particulate material;

a top shell having a horizontal section and a vertical wall section, said top shell being fixedly positioned with respect to said bottom shell to define therebetween a mold cavity.

8. The forming assembly as defined in Claim 7 wherein a portion of said second container extends over said vertical wall section and forms said reservoir.

9. The forming assembly as defined in Claim 7 wherein said horizontal sections and said vertical wall sections of said bottom and top shells are provided with side walls which cooperate in essentially fluid tight relationship therebetween.

10. The forming assembly as defined in Claim 9 wherein said side walls are upturned relative to said horizontal and vertical Wall sections.

11. The forming assembly as defined in Claim 7 wherein said top shell is provided with an orifice for introducing a foam-forming composition into said mold cavity.

12. A method for forming an impression of the gluteus maximus and at least a portion of the back of a human which comprises:

(a) positioning said gluteus maximus of said human on a first container disposed on a horizontal section, said container containing particulate material and thereafter positioning said portion of said back of said human on a second container juxtaposed to a vertical wall section, said vertical wall section being disposed relative to said horizontal section;

(b) evacuating said first container to a pressure below atmospheric whereby said particulate material becomes rigid by the frictional interlocking forces therebetween thereby forming a positive impression of the gluteus maximus;

(c) introducing particulate material into said second container from a reservoir thereof; and

(d) evacuating said second container to a pressure below atmospheric whereby said particulate material becomes rigid by the interlocking forces therebetween thereby forming said impression of said back portion.

13. The method as defined in Claim 12 wherein the pressure within said first container is raised to a pressure above atmospheric pressure prior to step (b) whereby said gluteus maximus nominally contacts the surface of the particulate material therein.

14. The method as defined in Claim 12 wherein the pressure within said second container is raised prior to step (c) to move said back away from said vertical wall.

15. The method as defined in Claim 12 wherein a spacer element is positioned between said first container and said horizontal section prior to step (a) .v

16. The method as defined in Claim 12 wherein a spacer element is positioned between, said second container and said vertical wall section prior to step (a).

17. A method for forming a contoured seat member of the gluteus maximus and at least a back of a human which comprises:

(a) positioning said gluteus maximus of said human on a first container material disposed on a horizontal section, said container containing particulate material and thereafter positioning said portion of said back of said human on a second container juxtaposed to a vertical wall section, said vertical wall section being disposed relative to said horizontal section;

(b) evacuating said first container to a pressure below atmospheric whereby said particulate material becomes rigid by the frictional interlocking forces therebetween thereby forming a negative impression of the gluteus maximus;

(c) introducing particulate material into said portion of said second container from a reservoir thereof;

(d) evacuating said second container to a pressure below atmospheric whereby said particulate material becomes rigid by the interlocking forces therebetween thereby forming a negative impression of said back portion;

(e) placing said containers within an L-shaped impression shell;

(f) fixedly positioning an L-shaped impression cover over said impression shell, the distance between facing walls thereof being greater than the thickness of said containers;

(g) introducing a rigid foam-forming composition into the zone between said containers and said cover shell and permitting said material to cure thereby forming a positive impression;

(h) positioning said negative impression within an L- shaped impression shell and an L-shaped impression cover fixedly positioned relative to each other, and

(i) introducing a foam-forming composition into the zone between said cover shell and said positive impression and permitting said foam-forming material to cure thereby forming said contoured cushion member.

18. The method as defined in Claim 17 wherein said contoured cushion member is upholstered to form a contoured cushion.

19. The method as defined in Claim 17 wherein a releasing agent is used on contact surfaces prior to steps (a) and 9 20. The method as defined in Claim 17 wherein said 3,112,987 foam-forming composition of step (g) forms a flexible 3,310,615 foam. 3,325,861 References Cited 3,589,967